Pressure regulating valve for rebreathing apparatus



Jan. 30, 1968 c L C RN ET AL I 3,366,108

PRESSURE REGULATING VALVE FOR REBREATHING APPARATUS Filed Sept. 20, 1965ABSORBER I CHARLES M. BLACKBURN i" ROSGOE GI BARTLETEJR.

I NVENTOR S 26 BY 6 Z k ATTO NEY a2 33 3/ 29. 30 7/ 'MM/ AGENT UnitedStates Patent OfiFice 3,365,198 Patented Jan. 30, 1968 3,366,108PRESSURE REGULATING VALVE FOR REBREATHING APPARATUS Charles M.Blackburn, Silver Spring, and Roscoe G.

Bartlett, .lr., Lime Kiln, Md., assignors to the United States ofAmerica as represented by the Secretary of the Navy Filed Sept. 20,1965, Ser. No. 488,828 8 Claims. (Cl. 128-142) The present inventionrelates to a rebreathing apparatus and, more particularly, to a devicewhich will extend the time a limited amount of oxygen may be used in anartificial respiration system.

Prior art respiration systems allow a fixed amount of oxygen to beinhaled during inspiration and thereafter exhaled to the atmosphere.Since less than the full amount of the available oxygen inhaled isconsumed by human lungs during each breath, a portion of the usableoxygen is wasted when exhaled directly to the atmosphere. If the exhaledair could be repeatedly used, removing the carbon dioxide therefrom andreplacing the oxygen as needed, the amount of oxygen consumed could besubstantially reduced.

It is, therefore, an object of the present invention to provide arebreathing apparatus which will extend the time a fixed quantity ofoxygen is capable of supporting the breathing needs of a person.

Another object is the provision of an improved valve for use in therebreathing apparatus of the present invention.

A further object of the present invention is to provide an improvedvalve incorporating a delay actuation mechanism.

Yet another object of the present invention is to provide a rebreathingapparatus which is light and compact and may be easily carried.

Still another object of the present invention is to provide arebreathing apparatus which is characterized .by simplicity ofconstruction, lOW cost, and ease of operation and use.

Other objects and many of the attendant advantages of this inventionwillbe readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings, wherein:

FIG. 1 is a schematic representation, showing the components of thepresent invention; and

FIG. 2 is an enlarged side elevation view, partly in section, showingthe elements of the valve unit.

Briefly, the rebreathing device of the present invention is comprised ofan oxygen mask connected through a carbon dioxide absorber to arebreathing bag. The rebreathing bag is equipped with two valves, i.e.,a relief valve which exhausts to the atmosphere when the pressure in thebag exceeds a predetermined limit, and a unidirectional valve whichcommunicates with a sensing chamber in a master valve unit. A diaphragmwithin the master valve unit sensing chamber is attached to a valve stemwhich, in turn, is attached to a slide valve adapted to open and closean oxygen line between the rebreathing bag and an oxygen supply. As theoxygen within the rebreathing bag is depleted, an accompanying decreasein pressure is reflected by the collapse of the diaphragm within thesensing chamber. The diaphragm movement opens the slide valve, throughthe connecting valve stem, thereby allowing oxygen to pass through theoxygen line and replenish the depleted oxygen within the rebreathingbag. The introduction of oxygen into the rebreathing bag increases thepressure on the diaphragm closing the slide valve.

Referring now to the-drawings, FIG. 1 shows a face mask 3, such as iswell known in the art, connected to a carbon dioxide absorber 4, alsowell-known in the art. The carbon dioxide absorber 4 is connected to asemirigid rebreathing bag 5 made of an elastomeric material, such assilicone rubber, which may be reinforced by a plurality of internalcircular ribs 6. A spring loaded relief valve 7, attached to the lowerportion of the rebreathing bag 5, opens at a predetermined pressure forventing the bag to the atmosphere, thereby preventing an excessivepressure buildup. A master valve unit 13 is located in an oxygen line 15which connects an oxygen supply 17 to the rebreathing bag 5. A meteringvalve 19 is located in the oxygen line 15 between the valve unit 13 andthe oxygen supply 17 for limiting the amount of oxygen flow through thevalve unit 13 when said valve unit is opened.

As best illustrated in FIG. 2, the master valve unit 13 is provided witha unidirectional valve 14 disposed within a cylindrical bore 20 formedin a first housing 21. The unidirectional valve 14 is adapted to placethe interior of the breathing bag 5 in communication with a sensingchamber 16 formed by the cylindrical bore 20 in the first housing 21 anda second cylindrical bore 22 in a second housing 23. The upper end ofthe second housing 23 is provided with a bore 24 which communicates withthe interior of the sensing chamber 16 through the smaller stepped bore25. A bleeder orifice 26 is located in the sidewall of the first housing21 and communicates between the sensing chamber 16 and the interior ofthe rebreathing bag 5. The one-Way valve 14 mounts in a relieved portion27 formed in the inner surface of the housing 21 and is comprised of adisk portion 28 having a stem 29 extending from its center lower surfacethrough a base portion 30 and terminating in a flange 31. The baseportion 30 has a plurality of ports 32 surrounding a centralcounterbored opening 33 through which passes the valve stem 29. Theunidirectional valve is attached to the housing 21 by a mounting plate34.

Dividing the interior of the sensing chamber 16 into two sections is adiaphragm 35 which is clamped in position between the first housing 2 1and the second housing 23. A port 36, in the second housing portion 22,vents the upper section of the divided sensing chamber 16 to the ambientatmosphere. A third housing 37 has a reduced lower portion 38 which fitstightly into the recess 24 in the second housing portion 23 therebyclosing the upper section of the sensing chamber 16. The upper housing37 is bored along its central axis to receive a tubular bearing seat 39having a journal bearing 40 mounted in each end. A valve stem 41,slidably mounted within the bearing 40, is secured to the center of thediaphragm 35 by a shoulder 42 and a nut 43 threadediy engaging athreaded portion 44 on the lower end of the valve stem 41. A compressionspring 45, mounted within the opening 25 and abutting the bottom surfaceof the upper housing 37, urges the diaphragm 35 towards a collapsedposition, as shown in phantom.

The bearing housing 39 is opened at 46 to communicate with an internallythreaded inlet port 47 to which is attached an oxygen line =15 leadingfrom the oxygen supply 17. An orifice 48, located above anddiametrically opposite the opening 46, communicates with a passageway49, 50, 5 1 and 52 which terminates in an outlet port 53. Attached tothe port 53 is the oxygen line 15 leading from the valve unit 13 to therebreathing bag 5. Covering the orifice 48 is a slide valve 58 which isslidably attached to the valve stem 41 by a square clip ring 59 locatedin a centrally relieved space 60, of substantially square cross-section,thereby allowing the valve stem 41 to travel up or down a fixed distancebefore engaging the slide valve 58. One side of the slide valve 58 issegmented, as at 61, so as to form a passageway for the passage ofoxygen from the inlet port to the orifice 48, while the sides of thesquare clip ring 59 engaging the sides of the centrally relieved space60 prevent rotation of the slide valve 58 on the valve stem 41. Aplurality of annular sealing rings 62 mount in grooves 63 between theaxial bore in the upper housing 37 and the bearing housing 39 to preventleakage. The valve unit 13 is secured in the rebreathing bag 5 by amounting ring 64 clamped around the lip 66 of the bag 5 and the housing23.

In operation, air from the rebreathing bag 5 is inhaled through thecarbon dioxide absorber 4 to the mask 3. During the inspiration stage,valves 7 and 14 remain closed. When, however, the breath is exhaledint-o the rebreathing bag 5, valve 14 opens thereby equalizing thepressure in the sensing chamber 16 with that in the bag 5. As the oxygenwithin the rebreathing bag 5 is depleted by repeated respirations, thepressure therein drops. This pressure drop causes the diaphragm 35 tocollapse under the combined urging of the ambient atmospheric pressure,communicated to the upper surface of the diaphragm 35 through port 36,and the compression spring 45. As the diaphragm 35 collapses, the valvestem 41 is drawn down with it until the clip ring 59 engages the lowersurface of the centrally relieved space 60 within the slide 58. Afterthe slide valve 58 is engaged it is also drawn down by the collapsingdiaphragm thereby exposing the orifice 48 and allowing oxygen to passinto the rebreathing bag 5. When the incoming oxygen has increased theinternal pressure in the rebreathing bag 5, as well as in the sensingchamber 16, the diaphragm 35 raises the valve stem 41 and closes theslide valve 58 over the orifice 48. Due to the arrangement the pressurewithin the rebreathing bag 5 is maintained equal to or slightly greaterthan ambient pressure while an adequate supply of oxygen is available atall times for the person using the device.

There has thus been described a rebreathing device which permits morecomplete utilization of the oxygen content of an artificial respirationsystem. In addition, due to the unique construction of the master valveunit 13, a high degree of reliability and safety is maintained byeliminating fatigue causing oscillations of the slide valve 58 throughthe use of a lost motion actuation system.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. A rebreathing apparatus comprising:

an oxygen mask;

a carbon dioxide absorber connected to said mask;

a rebreathing bag connected to said carbon dioxide absorber, said baghaving a pressure relief valve therean oxygen supply; and

a valve unit having an orifice therein for providing communicationbetween said oxygen supply and said rebreathing bag, said valve unitcomprising a housing having a sensing chamber therein, one-way valvemeans connecting said sensing chamber to said rebreathing bag, saidhousing being provided with a bleeder orifice interconnecting saidsensing chamber and said rebreathing bag, a diaphragm secured withinsaid sensing chamber, a valve stem secured to said diaphragm, a slidevalve slidably connected to said valve stem for movement relative to andwith said valve stem for opening and closing said orifice, means biasingsaid slide valve toward the open position;

whereby a reduction of pressure within said rebreathing bag caused bydepletion of the oxygen therein causes the slide valve, through themovement of the valve stem and diaphragm, to uncover the orifice therebyallowing oxygen to enter said bag.

2. A rebreathing apparatus in accordance with claim 1 wherein:

said slide valve is centrally relieved so as to form an interinal cavityof substantially square cross-section; and

said valve stem is provided with a square clip ring disposed withininternal cavity of said slide valve, thereby providing a delay in theactuation of said slide valve.

3. A rebreathing apparatus in accordance with claim 2 wherein:

said one-way valve means comprises a disk portion overlying an aperturedbase, said base forming the lower end wall of said housing, therebypermitting oxygen flow from said bag into said sensing chamher.

4. A valve unit for use in a rebreathing apparatus having an oxygenmask, a carbon dioxide absorber, an oxygen supply and a rebreathing bag,said valve unit comprising:

a housing having a passageway therethrough and a sensing chambertherein, said passageway providing communication between said oxygensupply and said rebreathing bag;

a unidirectional valve means providing communication between saidsensing chamber and said rebreathing bag, said housing being providedwith a bleeder orifice interconnecting said sensing chamber and saidrebreathing bag;

a diaphragm dividing said sensing chamber into two sections;

a valve stem secured to said diaphragm, said valve stem having a squareclip ring secured thereto; and

a slide valve slidably connected to said valve stem and adapted to openand close said passageway, means biasing said slide valve toward theopen position, said slide valve having an internal cavity ofsubstantially square cross-section, said square clip ring being disposedwithin said cavity to prevent rotation of said slide valve on said valvestem.

5. A rebreathing apparatus for use in an artificial respiration systemincluding a mask, a carbon dioxide absorber, and an oxygen supply, saidrebreathing apparatus comprising:

a rebreathing bag connected to said mask through said carbon dioxideabsorber;

a relief valve attached to said rebreathing bag for vent ing excesspressure therein;

a valve unit having a housing with a sensing chamber therein;

a unidirectional valve connecting said sensing chamber to saidrebreathing bag, said housing being provided with a bleeder orificeinterconnecting said sensing chamber and said rebreathing bag;

a diaphragm within said sensing chamber;

a valve stem connected to said diaphragm;

a slide valve mounted within said valve housing and connected to saidvalve stem, said slide valve adapted to open and close an orifice insaid valve unit housing, means biasing said slide valve toward the openposition;

a first oxygen line connecting said oxygen supply to one side of saidorfice; and

a second oxygen line connecting said rebreathing bag to the other sideof said orifice, whereby pressure within said bag causes said diaphragmto shift, thereby shifting said slide valve and allowing oxygen to entersaid bag through said orifice.

6. A rebreathing apparatus in accordance with claim 5 wherein:

said slide valve and valve stem are provided with a lost motion relayactuation means.

7. A rebreathing apparatus in accordance with claim 6 wherein:

said 10st motion delay actuation means comprises an internal cavitywithin said slide valve in which said valve stem reciprocates; and

a clip ring secured to said valve stem and disposed Within said cavity.8. A rebreathing apparatus in accordance with claim 7 wherein:

said internal cavity and clip ring are of substantially squarecross-section.

References Cited UNITED STATES PATENTS Bortin 128-203 XR Woodward 251-77XR Holm 128-1422 Finney 128-142 Tietze 128-142 RICHARD A. GAUDET,Primary Examiner. W. E. KAMM, Examiner.

1. A REBREATHING APPARATUS COMPRISING: AN OXYGEN MASK; A CARBON DIOXIDEABSORBER CONNECTED TO SAID MASK; A REBREATHING BAG CONNECTED TO SAIDCARBON DIOXIDE ABSORBER, SAID BAG HAVING A PRESSURE RELIEF VALVETHEREON; AN OXYGEN SUPPLY; AND A VALVE UNIT HAVING AN ORIFICE THEREINFOR PROVIDING COMMUNICATION BETWEEN SAID OXYGEN SUPPLY AND SAIDREBREATHING BAG, SAID VALVE UNIT COMPRISING A HOUSING HAVING A SENSINGCHAMBER THEREIN, ONE-WAY VALVE MEANS CONNECTING SAID SENSING CHAMBER TOSAID REBREATHING BAG, SAID HOUSING BEING PROVIDED WITH A BLEEDER ORIFICEINTERCONNECTING SAID SENSING CHAMBER AND SAID REBREATHING BAG, ADIAPHRAGM SECURED WITHIN SAID SENSING CHAMBER, A VALVE STEM SECURED TOSAID DIAPHRAGM, A SLIDE VALVE SLIDABLE CONNECTED TO SAID VALVE STEM FORMOVEMENT RELATIVE TO AND WITH SAID VALVE STEM FOR OPENING AND CLOSINGSAID ORIFICE, MEANS BIASING SAID SLIDE VALVE TOWARD THE OPEN POSITION;WHEREBY A REDUCTION OF PRESSURE WITH SAID REBREATHING BAG CAUSED BYDEPLETION OF THE OXYGEN THEREIN CAUSES THE SLIDE VALVE, THROUGH THEMOVEMENT OF THE VALVE STEM AND DIAPHRAGM, TO UNCOVER THE ORIFICE THEREBYALLOWING OXYGEN TO ENTER SAID BAG.